The present invention relates to a compound of general formula (I): in which: X is OH, NH2, NHOH or RNH, where R may be a linear or branched, saturated or unsaturated, C1-C10 alkyl radical, Y is H, or an electron-withdrawing group, in particular selected from NO2, CF3 or a halogen, R1 and R2 are H or a linear or branched, saturated or unsaturated, C1-C10 alkyl radical, F is a reactive functional group that can be activated by click chemistry.